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Knife marks and coil scratches - defects in cut to length line

Source:     Time:2021-01-27 Hits:

In the cut to length line process, defects sometimes appear. So what causes the defect? In today's article, Wuxi Bangzhou Machinery will take you to understand the causes of the two defects of knife marks and coil scratches and their corresponding solutions.

 

1. Knife prints

 

knife prints caused by the inner edge angle of the disc cutter on the surface of the steel strip. It occurs in the edge thickness of the knife, continuous or intermittent knife printing occurs.

 

(1) Knife prints caused by rubber ring and strip pressing. The knife prints are caused by too high apron in the middle width of the matching tool, too low apron in the narrow part, or too high pressure of the pressing strip and the discrepancy between the height of the knife and the pass plate.

 

(2) The cutter prints produced by partial cutters and rubber rings. For the disc cutter, when using the rubber ring, because the disc cutter swings when rotating, the surface of the finished product produces intermittent pressure, and the stress part is prone to wrinkles.


 (0.2-2)X1300mm automatic cut to length machine


(3) Wrinkles caused by the longitudinal swing of cutters and rubber rings. In addition to the above, the cutter prints occur when the cutter and rubber ring oscillate. That is, the cutter press on the surface of the product produced by intermittent knife prints. The main reasons are as follows: too large inner diameter and clearance of cutter shaft bending tool and too large inner diameter of spacer sleeve and clearance of cutter shaft (longitudinal swing of rubber ring).

 

(4) The prints produced by the auxiliary knife. In order to prevent the tool from twisting due to side pressure, a sub-cutter is usually equipped next to the main cutter. At this time, the outer diameter of the two blades is slightly different. Once a sharp sub-knife is used, a knife mark will be produced. This kind of mark can be prevented by using once-used knives with rounder edges as auxiliary knives or by using the same external diameter auxiliary knives.

 

2. Coiling scratches

 

When the coil is coiled in a relaxed state, the inner layers of the coil will slip. Various scratches will occur on the surface of the steel plate, as well as scratches caused by repeated friction of the scratched points. In addition, even if the coil is normally coiled, scratches will occur when the coil is coiled under tension beyond normal tension.


 1600mm stainless steel Coil (roll) Cut to Length line


(1) Coiling scratches on the uncoiler. When the counter-tension of uncoiler exceeds the coiling tension of base metal, or when the brake of uncoiler is insufficient, or when the pressure of pressure stop roll of uncoiler is insufficient, the coil will be relaxed and scratch will occur. In addition, the loose coil will be re-tightened and scratched when it is uncoiled on the machine. Once the counter-tension of the uncoiler is too large, the steel plate will suddenly tighten when it is opened and loosened, and there will also be scratches. So measures should be taken to reduce the braking force when the work is finished.

 

(2) Coiling scratches on the winder. Loose rolls are more likely to occur when the cut to length line stops and starts again. Relaxation of shearing outer ring, transverse misalignment of coil when unwinding, etc. will cause scratches. In addition, coiling scratches will occur when the loose steel coil is inserted into the mandrel and re-coiled.

 

(3) Coiling abrasion in hand expander. In the state of insufficient tension, the loosened coil will be wrapped in dislocation and scratch when it is grasped by hand expander and contractor. In addition, scratches also occur when the strips in the looper sway and overlap horizontally.

 

Wuxi Bangzhou Machinery is the professional cut to length line manufacturer. Our company specialized in designing and producing all kinds plates processing machines.We have tremendous strength on technical and professional production capability. If you want more details about our cut to length line or other kinds of machines, welcome to contact with us!



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